(a) Field of the Invention
The present invention relates to novel high polymers and to ferroelectric liquid crystal compositions containing the same. More particularly, the present invention relates to novel high polymers and ferroelectric liquid crystal compositions which are suitable materials for liquid crystal devices used in optoelectronics fields, for example, digital display devices of desk calculators, clocks and watches, dot-matrix display devices, electrooptic shutters, electrooptic diaphragms, optical modulators, optical-path transfer switches in optical communication systems, memories, liquid crystal printer heads and varifocal lenses.
(b) Description of the Related Art
Display devices utilizing low molecular weight liquid crystals have been used widely for digital display of desk calculators, clocks and watches, etc. In these fields of utilization, the conventional low molecular weight liquid crystals are generally supported between a couple of glass substrates spaced from each other in microns. However, such an adjustment of the space has been impracticable in the production of large picture planes or curved picture planes. A means which has been employed for solving the problem is the development of liquid crystal polymers or of liquid crystal compositions containing low molecular weight liquid crystals and high polymers.
For example, in Japanese Patent Application Kokai Koho (Laid-open) No. 63-284291 proposed are liquid crystal compositions comprising low molecular weight liquid crystals and polymer liquid crystals having asymmetric carbon atoms. However, the side chain polymer liquid crystals exemplified therein have acrylate main chains or siloxane main chains, which cannot provide sufficient spaces between side chains, and increasing their molecular weights makes it difficult to mix the low molecular weight liquid crystals in a sufficient quantity to attain a great increase in response speed. That is, the liquid crystal compositions have difficulty in uniting polymeric properties and high speed response.
As an attempt to unite polymeric properties and high speed response by mixing non-liquid-crystalline high polymers and low molecular weight liquid crystals, Japanese Patent Application Kokai Koho (Laid-open) No. 61-47427 discloses compositions which are endowed with self shape retention by blending amorphous polymers into low molecular weight liquid crystals. However, the compositions involve a problem in that after allowed to stand for a long time, they are apt to separate because of the liquid crystal regions dispersed in the matrix of the high polymers (resins). Further, the compositions are poor in contrast because of the island-dispersion of the low molecular weight liquid crystals, and such a dispersion system makes it difficult to control their orientation. In Japanese Patent Application Kokai Koho (Laid-open) Nos. 62-260859 and 62-260841 disclosed are ferroelectric composite films containing thermoplastic resins and low molecular weight liquid crystals which are compatible with each other. However, it is difficult to select the low molecular weight liquid crystals compatible with the thermoplastic resins, and it is also difficult to control the orientation of the low molecular weight liquid crystals. Further, the low molecular weight liquid crystals are limited to ferroelectric liquid crystals. In Japanese Patent Application Kokai Koho (Laid-open) No. 1-198683 disclosed are compositions which comprise polymers containing proton donors (or proton acceptors) and low molecular weight liquid crystals containing proton acceptors (or proton donors). However, the compositions also involve a problem in that the structures of the polymers and the low molecular weight liquid crystals are limited to those having proton donors or proton acceptors.